Question

Помогите пожалуйста СРОЧНО.

Answer 1

Объяснение:

1.

$sin34^0*cos17^0-cos34^0*sin17^0=sin34^0*cos17^0-sin17^0*cos34^0=\\=\frac{1}{2}*(sin17^0+sin51^0 )-\frac{1}{2} *(sin(-17^0)+sin51^0)=\\=\frac{1}{2} *(sin17^0+sin51^0+sin17^0-sin51^0)=\frac{1}{2}*2*sin17^0=sin17^0.$

2.

$cos(\alpha -\beta )-cos\alpha *cos\beta =cos\alpha *cos\beta +sin\alpha *sin\beta -cos\alpha *cos\beta =sin\alpha *sin\beta .$

3.

$cos(\alpha -\beta )=cos\alpha *cos\beta +sin\alpha *sin\beta .\\sin(\alpha -\beta )=sin\alpha *cos\beta -cos\alpha *sin\beta .$